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KAFKA-9866: Avoid election for topics where preferred leader is not in ISR #8524

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Merged
junrao merged 6 commits into from
Apr 27, 2020
Merged

KAFKA-9866: Avoid election for topics where preferred leader is not in ISR #8524

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44eea04
Avoid starting election for topics where preferred leader is not in s…
leonardge Apr 21, 2020
29632f7
Refactored the code and fixed bug in the integration test.
leonardge Apr 22, 2020
172960f
Refactored according to comments.
leonardge Apr 23, 2020
24c6d42
Kept the code to be consistent.
leonardge Apr 24, 2020
dc67b99
Reverted style change.
leonardge Apr 24, 2020
2fa3cee
Renamed helper function after review.
leonardge Apr 25, 2020
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13 changes: 12 additions & 1 deletion core/src/main/scala/kafka/controller/KafkaController.scala
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Original file line number Diff line number Diff line change
Expand Up @@ -1068,12 +1068,23 @@ class KafkaController(val config: KafkaConfig,
val candidatePartitions = topicsNotInPreferredReplica.keys.filter(tp => controllerContext.isReplicaOnline(leaderBroker, tp) &&
controllerContext.partitionsBeingReassigned.isEmpty &&
!topicDeletionManager.isTopicQueuedUpForDeletion(tp.topic) &&
controllerContext.allTopics.contains(tp.topic))
controllerContext.allTopics.contains(tp.topic) &&
canPreferredReplicaBeLeader(tp)
)
onReplicaElection(candidatePartitions.toSet, ElectionType.PREFERRED, AutoTriggered)
}
}
}

private def canPreferredReplicaBeLeader(tp: TopicPartition): Boolean = {
val assignment = controllerContext.partitionReplicaAssignment(tp)
val liveReplicas = assignment.filter(replica => controllerContext.isReplicaOnline(replica, tp))

@ijuma ijuma Apr 27, 2020

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We also do controllerContext.isReplicaOnline(leaderBroker, tp) in the caller. Do we also need it here?

@junrao junrao Apr 27, 2020

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Good point. We can get rid of the isReplicaOnline() check in the caller. @leonardge : Could you summit a followup minor PR?

@leonardge leonardge Apr 27, 2020

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Sure thing!

val isr = controllerContext.partitionLeadershipInfo(tp).leaderAndIsr.isr
PartitionLeaderElectionAlgorithms
.preferredReplicaPartitionLeaderElection(assignment, isr, liveReplicas.toSet)
.nonEmpty
}

private def processAutoPreferredReplicaLeaderElection(): Unit = {
if (!isActive) return
try {
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4 changes: 2 additions & 2 deletions core/src/test/scala/unit/kafka/controller/ControllerIntegrationTest.scala
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Expand Up @@ -433,8 +433,8 @@ class ControllerIntegrationTest extends ZooKeeperTestHarness {
TestUtils.createTopic(zkClient, tp.topic, partitionReplicaAssignment = assignment, servers = servers)
waitForPartitionState(tp, firstControllerEpoch, otherBrokerId, LeaderAndIsr.initialLeaderEpoch,
"failed to get expected partition state upon topic creation")
servers(1).shutdown()
servers(1).awaitShutdown()
servers(otherBrokerId).shutdown()
servers(otherBrokerId).awaitShutdown()
TestUtils.waitUntilTrue(() => {
val leaderIsrAndControllerEpochMap = zkClient.getTopicPartitionStates(Seq(tp))
leaderIsrAndControllerEpochMap.contains(tp) &&
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